<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Title</title>
</head>
<body>
<input id="btn1" type="button" value="开启">
<input id="btn2" type="button" value="关闭">
<script>
	window.onload = function () {
		var oBtn1 = document.getElementById("btn1");
		var oBtn2 = document.getElementById("btn2");
		var timer = null;
		oBtn1.onclick = function () {
			timer = setInterval(function () {
			  console.log('abc')
			},1000)
		}
		oBtn2.onclick = function () {
		  clearInterval(timer);
		}
	}
</script>
</body>
</html>